Hello,
I am using quectel GNSS Module L86-M33 implemented on an electronic card to measure latitude, longitude, altitude, time and date during flights under meteorolgical ballons.
These measurements made with the GNSS module are coupled with measurements of pressure on our electronic card, along with other parameters.
In a nominal flight, during the ascent and the descent of the balloon (0 to 30km high), the pressure (measured by a sensor on the electronic card) and the altitude (measured by the GNSS module) are both correlated.
In recent flights, I noticed a decorrelation between these two parameters, happening at the ballon burst when the altitude is at his maximum. This decorrelation last during the whole descent, but recovers at the end of the flight.
We see a shift in the values of altitude, latitude and longitude measured by the GNSS module, which goes back to normal at the end of the descent. There is no discontinuity in time or any missing values.
We would like to know if you would have any idea on how to understand this issue.
Could this be due to an intern process in the GNSS module, likely to be delayed values taken at a given time that would not be reinitialized automaticly in a way to be delayed throughout the flight?
I thank you for your time,
Axel Guedj